Molecule could be key to depression

Research into depression has shown a key molecule could be vital to the condition – and why some drugs stop treating it effectively.

Experts at Edinburgh University have pinpointed a key molecule they think may protect the brain from depression.

Their study also sheds light on why a particular category of antidepressant drug stops working in some people, researchers believe.

The team studied mice bred to have defects in their ability to activate the molecule, known as eIF4E.

These animals showed signs of depression, including reduced levels of the hormone serotonin – a hallmark of the condition.

The mice also demonstrated behavioural changes linked to depression, such as lacking interest in food.

Treatment with a commonlyprescribed antidepressant called fluoxetine also failed to produce a response in the mice, the university said.

Scientists said this suggests that activation of the molecule is required to experience the beneficial antidepressant effects of fluoxetine.

This could help explain why some patients stop responding to particular drugs, researchers say.

Other studies have shown defects in the molecule are linked with neurological conditions such as autism.